2bo4
From Proteopedia
Dissection of mannosylglycerate synthase: an archetypal mannosyltransferase
Structural highlights
Function[MGS_RHOMR] Involved in the biosynthesis of the stress protectant 2-O-alpha-D-mannosyl glycerate (MG) which is produced in response to growth at supraoptimal temperature and salinity, and protects several enzymes against inactivation by temperature, freeze-drying and osmotic stress. Catalyzes the condensation of alpha-GDP-D-mannose (GDP-Man) with D-glycerate to produce alpha-mannosyl-D-glycerate. It is specific for GDP-Man, but it can also use alpha-GDP-D-glucose (GDP-Glc), beta-GDP-D-fuctose, alpha-UDP-D-mannose and alpha-UDP-D-glucose as sugar donors. It is specific for D-glycerate, but it can also use D-lactate and glycolate as sugar acceptors. This reaction occurs with a net retention of anomeric configuration; the newly formed glycosidic linkage has the same alpha configuration as the sugar donor.[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe enzymatic transfer of activated mannose yields mannosides in glycoconjugates and oligo- and polysaccharides. Yet, despite its biological necessity, the mechanism by which glycosyltransferases recognize mannose and catalyze its transfer to acceptor molecules is poorly understood. Here, we report broad high-throughput screening and kinetic analyses of both natural and synthetic substrates of Rhodothermus marinus mannosylglycerate synthase (MGS), which catalyzes the formation of the stress protectant 2-O-alpha-D-mannosyl glycerate. The sequence of MGS indicates that it is at the cusp of inverting and retaining transferases. The structures of apo MGS and complexes with donor and acceptor molecules, including GDP-mannose, combined with mutagenesis of the binding and catalytic sites, unveil the mannosyl transfer center. Nucleotide specificity is as important in GDP-D-mannose recognition as the nature of the donor sugar. Structural dissection and high-throughput screening of mannosylglycerate synthase.,Flint J, Taylor E, Yang M, Bolam DN, Tailford LE, Martinez-Fleites C, Dodson EJ, Davis BG, Gilbert HJ, Davies GJ Nat Struct Mol Biol. 2005 Jul;12(7):608-14. Epub 2005 Jun 12. PMID:15951819[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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